The Difference Between a Panhead and a Shovelhead

At ChopperExchange, we get calls all the time from private sellers who want to list their Panhead or Shovelhead, but can’t locate the model on our website. There is a logical reason why. Although riders may refer to their Harleys as a Panhead or a Shovelhead, neither are names of models. They are really names of the engine.

It’s not our first time around, so we know how to list these bikes. The same goes for long time riders who can tell these bikes apart no problem. But for a new rider telling these bikes apart can be confusing, especially when there are also Knucklehead and Flathead engines.

The distinguishing feature of each of these engines are the heads which serve as valve covers. Each head is uniquely shaped and the inspiration behind each engine name. If you are new to the biker world or just unsure, we are here to help you identify all four engines at first glance.

The Flathead (1929 – 1975)

The Flathead engine debuted in 1929 and is the oldest of the four engines. The 1930 V model Big Twin was the first bike with the Flathead engine. The engine’s name is inspired by its flat-topped, vented cylinder heads identified in the image below.

The Knucklehead (1936 – 1947)

The Knucklehead engine was produced from 1936 to 1947 until it was replaced by the Panhead. They were originally called “OHVs” until the nickname “Knucklehead” was created by the California motorcycle culture of the late 1960s. The name was inspired by the distinct shape of the valve covers, which have contours that resemble the knuckles on a person’s fist.

The Panhead Engine (1948 – 1965)

Panhead engines were produced from 1948 to the mid ‘60s when it was replaced by the Shovelhead. Its inception was just in time for the postwar motorcycle boom. The valve covers on these bikes look like small cake pans. The purpose of the Panhead design was to help with oil containment, however, it wasn’t successful. Panheads still leak oil from the top end.

The Shovelhead Engine (1966 – 1985)

The Shovelhead engine was produced from the mid ‘60s to the early ‘80s. Harley created the Shovelhead mainly to produce more power for their heavier bikes with electric start and rear suspension. The shallow chambers of the Shovelheads helped with cooling and worked better at higher compression ratios; however, the engine went through a series of updates. The heads resemble the curve of a shovel, hence the name. This type of engine is the most difficult to identify because the shape does not resemble that of a traditional shovel. Instead it looks more like a coal shovel flipped upside down.

Now that you’ve read this blog, you won’t look like a knucklehead next time you try to identify an older model. The shape of the engine heads will tell you what kind of engine it is.